The present invention relates to a shutter release apparatus operated by a shutter release button in a camera.
As an improvement on conventional mechanical release mechanisms, there is known a method whereby depression of a shutter release button closes an electrical switch allowing the energizing of an electromagnetic device, which releases the camera's shutter. There are also known means whereby, in conjunction with the operating of such a mechanism, electrical switching may be provided for the operation of an overall or general power-related system, such as for automatic exposure control. Such switching may precede the activation of the electromagnetic release device.
For example, there is known a system whereby a vertical rod member on the axis of the shutter release button moves downwards with the depression of the button. Extending horizontally from the surface of the rod member are multiple protrusions which move downwards with the rod member and, by simple mechanical force, serve to push closed or open various spring switches disposed in their paths.
Similarly, there is known a system whereby the shutter release button with a rod member as above moves downwards within a sleeve which is also movable vertically. Means are provided whereby, after a predetermined amount of vertical travel, the shutter release button engages the movable sleeve which itself also then moves downwards. The rod member serves to operate one electrical switch while the movable sleeve serves to operate another. In the shutter release mechanism, the operational timing of each switch is set different, so that, for example, a switch which is turned on earlier is employed as a main switch for activation of the shutter release mechanism while another switch which is turned on with a certain time lag thereafter is employed as a switch for activating a magnetic release device.
However, in both of the foregoing examples, a large number of parts are required and sequential timing is determined by physical separation of the moving members and is relatively difficult to predetermine with the necessary accuracy, particularly requiring delicate adjustment of the stroke of the release button and the sequential operation of a first switch and a second switch. As a result, considerable effort and expense to manufacture are required.
In addition, they both require a relatively large space within the camera body because of the various protrusions and mechanical spring switches required, and both leave the most delicate parts thereof open and susceptible to the effects of dust and moisture.